Add pluralize utility with unit tests

bowtie/_cli.py

@@ -35,6 +35,7 @@
     NoSuchImage,
     StartupFailed,
 )
+from bowtie._utils import pluralize
 from bowtie.exceptions import (
     _ProtocolError,  # type: ignore[reportPrivateUsage]
 )
@@ -207,14 +208,13 @@ def _failure_table(
     summary: _report._Summary,  # type: ignore[reportPrivateUsage]
     results: list[tuple[tuple[str, str], _report.Count]],
 ):
-    test = "tests" if summary.total_tests != 1 else "test"
     table = Table(
         "Implementation",
         "Skips",
         "Errors",
         "Failures",
         title="Bowtie",
-        caption=f"{summary.total_tests} {test} ran\n",
+        caption=f"{pluralize(summary.total_tests, 'test')} ran\n",
     )
     for (implementation, language), counts in results:
         table.add_row(
@@ -252,12 +252,11 @@ def _validation_results_table(
     summary: _report._Summary,  # type: ignore[reportPrivateUsage]
     results: Iterable[tuple[Any, Iterable[tuple[Any, dict[str, str]]]]],
 ):
-    test = "tests" if summary.total_tests != 1 else "test"
     table = Table(
         Column(header="Schema", vertical="middle"),
         "",
         title="Bowtie",
-        caption=f"{summary.total_tests} {test} ran",
+        caption=f"{pluralize(summary.total_tests, 'test')} ran",
     )
 
     for schema, case_results in results:

bowtie/_utils.py

@@ -0,0 +1,22 @@
+"""
+Small, generic helpers shared across Bowtie's modules.
+"""
+from __future__ import annotations
+
+
+def pluralize(count: int, noun: str, plural: str | None = None) -> str:
+    """
+    Combine a count with the singular or plural form of a noun.
+
+    >>> pluralize(1, "test")
+    '1 test'
+    >>> pluralize(0, "test")
+    '0 tests'
+    >>> pluralize(2, "test")
+    '2 tests'
+    >>> pluralize(2, "story", plural="stories")
+    '2 stories'
+    """
+    plural = plural or f"{noun}s"
+    word = noun if count == 1 else plural
+    return f"{count} {word}"

tests/test_utils.py

@@ -0,0 +1,25 @@
+from bowtie._utils import pluralize
+
+
+def test_pluralize_singular():
+    assert pluralize(1, "test") == "1 test"
+
+
+def test_pluralize_plural():
+    assert pluralize(2, "test") == "2 tests"
+
+
+def test_pluralize_zero():
+    assert pluralize(0, "test") == "0 tests"
+
+
+def test_pluralize_negative():
+    assert pluralize(-1, "test") == "-1 tests"
+
+
+def test_pluralize_custom_plural():
+    assert pluralize(2, "story", plural="stories") == "2 stories"
+
+
+def test_pluralize_custom_plural_singular_unaffected():
+    assert pluralize(1, "story", plural="stories") == "1 story"